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Purpose: Nontyphoidal Salmonella (NTS) is a common pathogen responsible for acute gastroenteritis among all ages; however, information on the prevalence, serotypes, and antibiotic susceptibility of NTS isolates is limited. We aimed to explore the characteristics of NTS isolated from paediatric patients in Guangzhou, China. Methods: This was a retrospective study of 4586 stool culture collected at Guangzhou Women and Children’s Medical Center from 2014 to 2016. Results: We identified 220 (4.80%) NTS isolates in stool samples. Fourteen serotypes were identified among the 220 NTS isolates. Salmonella serotype Typhimurium was the most common serotype, representing 69.09%. The highest rate of resistance was recorded in relation to AMP (76.61%), followed by SXT (29.95%), CTX (29.93%), CHL (29.77%), CAZ (23.20%), CIP (7.51%), and CFS (7.18%). The resistance rates of NTS and serotype Typhimurium to CAZ in 2015 were significantly higher than those in 2014. The average hospitalisation duration of inpatients infected by NTS resistant to three or more clinically important agents was significantly longer than that of patients infected with NTS with less antibiotic resistance. Conclusion: NTS represents a major cause of paediatric gastroenteritis in Guangzhou, China, and the high level of resistance to third-generation cephalosporins coupled with increasing resistance to quinolones among isolated NTS from paediatric gastroenteritis is a serious public health concern that requires continued monitoring and rational usage of antibiotics. Keywords: Salmonella, Gastroenteritis, Paediatric, Serotyping, Drug resistance

Conventional culture method for detecting Group B streptococcus (GBS), a common pathogen of neonatal meningitis and sepsis, is time-consuming and unsensitive. Even though real-time fluorescence PCR-based molecular method is more accurate, it need special instrument and elaborate protocol. Here, we established a novel molecular method combining recombinase polymerase amplification with lateral flow strips for detecting GBS. The cAMP factor (cfb) gene is a highly specific and sensitive biomarker to identify GBS and is detectable by using 100 genomic copies as the amplification template. Clinical performance of this assay was evaluated by testing 130 samples, in comparison with culture method and real-time fluorescence PCR, and the results achieved 100% accuracy, which were the same with those of real-time fluorescence PCR, and were better than those of culture method with false-negative detection. This study provides a rapid and visual method, with clinical potential, for the detection of GBS infection of patients.

This article has been retracted: please see Elsevier Policy on Article Withdrawal (https://www.elsevier.com/about/our-business/policies/article-withdrawal). This article has been retracted at the request of the authors. There is significant discrepancy in the genomic characteristics between the currently and previously dominant GBS (2018) and previously dominant GBS (2013-2014). The dramatically rapid and unexpected evolution of GBS strains has led to the significant discrepancy from recent findings which makes all the authors strongly concerned that this will influence the accuracy and validity of GBS treatment and therapy if based on the current manuscript. For example, the genomic difference between the currently prevalent type (II and III) and previously prevalent type (III) is considerably diverse, for which the pathogenic and virulent characteristics of the strains are very different. As all authors have a strong sense of responsibility and expertise in clinical microbiology, agreed by all authors, on behalf of all authors of this manuscript, the authors consequently request for article withdrawal for this manuscript.

In the Viable but Non-Culturable (VBNC) state, microorganisms may survive under severe external environment. In this study, the specificity and sensitivity of PMA-LAMP assay on the detection of Vibrio Parahemolyticus (V. parahemolyticus) has been developed and evaluated, with further application on a number of food-borne V. parahemolyticus strains. Six primers were designed for recognizing 8 distinct targeting on tlh, tdh and trh gene. Through specific penetration through the damaged cell membrane of dead cells and intercalating into DNA, PMA could prevent DNA amplification of dead bacteria from LAMP, which enabled the differentiation of bacteria between VBNC state and dead state. The established PMA-LAMP showed significant advantage in rapidity, sensitivity and specificity, compared with regular PCR assay. The applicability had also been verified, demonstrating the PMA-LAMP was capable of detection on V. parahaemolyticus.